I. Field of the Invention
The present invention relates to fuel-air mixing systems for internal-combustion engines and, more particularly, to a fuel-air mixing system which automatically removes excess fuel droplets from the fuel-air mixture provided by the carburetor.
II. Description of the Prior Art
It is well known that satisfactory, idle, or minimum power operation of an internal-combustion engine ordinarily requires admitting an inlet charge which is relatively rich. There are several factors leading to this requirement of the rich fuel-air mixture, but the fundamental factor is that a predetermined flame temperature must be maintained in a combustion chamber to support the combustion of the fuel-air mixture. Since this flame temperature is an average of the burned and unburned charge portion temperatures, the predetermined temperature is ordinarily maintained by elevating the burned charge temperature at low-power operation by means of the admission of the rich fuel-air mixture. It is also known that the admission of such rich mixtures under low power and part throttle operation of the engine tends to promote an exhaust which is high in unburned hydrocarbon content.
To alleviate this condition, numerous systems have been proposed in the prior art. Many of the systems employ various types of fuel-mixture preheaters which function to vaporize the fuel in the mixture before the mixture enters the intake manifold of the engine for the purpose of improving the efficiency of the engine. In a gasoline engine the preheater is customarily connected between the outlet of the carburetor and the inlet of the intake manifold and is in the form of a heat exchanger which utilizes either the hot exhaust gases of the engine or the hot water in the engines's coolant system as a source to heat the vaporized fuel. In some heat exchangers, baffles are arranged in the path of the stream of the fuel-air mixture for the purpose of retarding the flow of the fuel droplets within the heating chamber until sufficient vaporization has taken place. One example of such a fuel droplet-retarding baffling arrangement is described in U.S. Pat. No. 2,232,413; and a second example is disclosed in U.S. Pat. No. 3,645,243. Other examples of attempts which have been made to increase the efficiency of internal-combustion engines are disclosed in U.S. Pat. Nos. 2,617,633; No. 3,554,174; and No. 3,797,468.
Each of the aforementioned systems generally are inordinately complex in a mechanical sense and have not yet demonstrated any significant commercial practicality.